However, for your edification I post the following link to the U.S. Statute which covers the citizenship of children born to American citizens in the Canal Zone. Note that it requires only one parent to be an American citizen in order to confer American citizenship on the child. Since no one contends that the Obamanation was born in the Canal Zone it has no application to him and is totally irrelevant to his situation.
Do you see the words "Natural Born Citizen" anywhere in that section of the code? It's not there. Even if it was, the Congress cannot, by the simple passage of a law, change the meaning of Constitutional terms.